Prenatal diagnosis of short-rib polydactyly syndrome type 3 (Verma-Naumoff type) by three-dimensional helical computed tomography

Abstract

We present a case of short-rib polydactyly syndrome (SRPs) type 3 in which accurate prenatal diagnosis was feasible using both ultrasonography and 3D-CT. SRP encompass a heterogeneous group of lethal skeletal dysplasias. However, the phenotypes overlap with those of nonlethal skeletal dysplasias (i.e. Ellis-van Creveld syndrome and Jeune syndrome). As accurate prenatal diagnosis of SRP is helpful for parents, we used 3D-CT in the early third trimester to examine a fetus suggested to have phenotypes of 'short-rib dysplasia group' on ultrasonography. 3D-CT showed mild modification of the vertebral bodies, small ilia with horizontal acetabula and triangular partial ossification defects, and subtle metaphyseal irregularities of the femora. These CT findings and an extensive literature search regarding the phenotypes of various diseases categorized as short-rib dysplasia group led to a correct prenatal diagnosis of SRP type 3. This case exemplified the usefulness of 3D-CT for the precise prenatal diagnosis of skeletal dysplasias.